Julie packed 18 dvds in each of 4 boxes. she packed 15 dvds in each of 5 boxes. she has 8 dvds left over. how many dvds does julie have?

Can someone explain the elimination method to me for this problem?

Atriangular bandana has an area of 46 square inches. the height of the triangle is 5 3 4 inches. enter and solve an equation to find the length of the base of the triangle. use b to represent the length of the base.

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 - 4x - 5 = 0